THE EFFECT OF INCREASED ACTIVITY OF THE SYMPATHETIC SYSTEM IN THE INHIBITION OF WATER‐DIURESIS BY EMOTIONAL STRESS

Abstract

1. Tests of the effect of emotional stress produced by 30‐60 seconds faradic stimulation during water‐diuresis in normal dogs have revealed two types of inhibition of urine flow: a rapid inhibition which is abolished by section of the splanchnics and denervation of the kidneys and suprarenal (“denervation”), and a slow inhibition due to release of antidiuretic substance from the posterior lobe of the pituitary. 2. In 21 normal bitches, 3 gave large slow inhibitions in all tests, 7 always gave rapid inhibitions only, and 11 gave a large slow inhibition in some tests. After “denervation” a large slow inhibition was found in all tests in all animals. 3. The slow inhibition thus revealed could be prevented by the injection of adrenaline just before the application of the faradic stimulus. 4. Adrenaline did not diminish the inhibition produced by the injection of post‐pituitary extract. 5. It was concluded therefore, that after an injection of adrenaline, the resultant absence of the large slow inhibition produced by emotional srtess in the “denervated” animal was due to failure of release of the antidiuretic substance, and not to failure of the released substance to act on the kidney. 6. The irregular appearance of the slow inhibition in normal dogs is thus explicable in terms of failure of the release of antidiuretic substance from the posterior lobe owing to increased sympathetic activity during emotional stress. 7. Evidence has not yet been sought to determine the relative rôles of adrenaline and the renal nerves in the rapid type of inhibition, nor to decide whether the prevention of release of the antidiuretic hormone is due to adrenaline specifically or to an increase in arterial pressure.